Electric clock system



Feb. 11, 1936. c. E. LARRA BEE 2,030,455

LECTRIG CLOCK s F 1936- c. E. LARRABEE 2,030,455

ELECTRIC CLOCK SYSTEM Filed July 16, 1932 3 Sheets-Sheet 2 v 6 1W B Feb.11, 1936. c. E. LARRABEE ELECTRIC CLOCK SYSTEM Filed July 16, 1952 3Sheets-Sheet 3 R v um mu MN \WN w mw Ai-roRNEY Patented Feb. 11,

UNITED STATES PATENT OFFICE by mesne assignments,

Machines corporation, corporation of New-York Application July 10, 1932,w No. 622,008

SCIaImI.

This invention relates to electric clock systems and more particularlyto electric clock systerm of the minute impulse type, which arecontrolled or supervised by a master clock.

; Frequently, two master clocks are used in connection with thesupervision of electric clock systems in which one of the two masterclocks is carried as a spare or reserve clock to be used in the event ofthe other master clock becoming incapacitated. This is generally takencare of by a throw-over switch which is operated manually, but this isnot entirely satisfactory as the failure of the clock can only bedetected when the failure of the system is noted, at which time, whoever 5 is in charge of the system must immediately go to the controlswitches and throw the control from the master clock, which has failed,to the other master clock which is intended to act in such emergencies.The present invention relates to accomplishing this throw-overautomatically upon the failure of the master clock.

It is therefore one object of this invention to provide a device forautomatically throwing the the control of an electric clock system fromone master clock to another master clock.

Another object of this inventionis to provide a device for detecting thefailure of a master clock, and for giving a warning upon the failure ofsaid clock.

Still another object is to provide an electric clock system controlledby a supervising master clock and a device operable by said master clockand an auxiliary master clock which determines which of the two masterclocks shall control the 35 system.

A further object is to provide a device operable by a supervising masterclock and an auxiliary master clock in which the failure of thesupervising master clock causes the control of an elec- 40 tric clocksystem to be transferred to the auxiliary master clock and causes asignal or warning to be given and in which the failure of the auxiliaryclock causes only a warning signal to be given.

A still further object is to provide a differenti- 45 ally operatedmechanism operated from two master clocks in which the failure of one ofthe master clocks will cause the control of an electric clock system tobe transferred to the other master clock.

Other objects and advantages of this invention will be apparent from thespecification and the accompanying drawings which show one embodiment ofthis invention and wherein similar reference numerals indicate similarparts and-wherein 55 the drawings:

Fig. 1 shows a general front elevation of a suitable master clock.

Fig. 2 shows a side detailed view of the differential mechanismcontrclledby two magnet driven units. 5

Fig. 3 is a detail view of the transferring device takenon line 3-301Fig.2.

Fig. 4 shows the wiring diagram of such a system.

The type of electric clock system shown in the preferred embodiment ofthe specification and as illustrated is an hourly supervised orsynchronized system such as shown in the patent to J. W. Bryce, No.1,687,491. The master clock may be of any desired form, such forexample, as is shown in the patent to J. w. Bryce, No. 1,390,018.

Referring now to Fig. 1, the master clock includes the usual time trainadapted to drive the minute arbor l0 which makes one revolution perhour. The usual verge mechanism I I is provided. Fixed to the minuteshaft are a pair of cams i2 and II which cams are shaped in position tocontrol a pair of contacts I on which the position of the upper contactand its arm is controlled by cam l1 and the position of the lowercontact and its arm is controlled by cam l2.

Also fixed to the minute arbor I0 is a cam I5 which is adapted to openand close two pairs of contacts I! and 20. In addition, the master clockis provided with the usual minute impulm contacts II which arecontrolled in the usual way from a cam ll making one revolution perminute or otherwise, as is the custom in clocks of this sort. Foradvancing or steppingforward the secondary clocks, there is providedquick acting contacts l9, which are preferably operated by attaching onthe verge mechanism I I. These contacts I! will close at every swing ofthe pendulum, the bob of which would be attached to the lower end of thependulum rod 2|.

The secondary clock movements which would be controlled by this masterclock are shown disgrammatically in Fig. 4 at 22. The cam 23 on each ofthe secondary clocks is fixed to the minute arbor and actuates thecontacts 25 and 28 by means of the cam follower 24 in identically thesame manner as described in the patent to Bryce No. 1,687,491. Themaster clock through its contacts ll, II, II and I9 sends out normalimpulses and rapid impulses during the synchronizing period over thewires A and B for the normal operation and synchronization of thesecondary clocks 22 in the same manner as described in the previouslymentioned patent.

In the operation of this invention two master as clocks are used, one ofwhich will hereinafter be described as the supervising master clock and,the other as the auxiliary master clock. -Both of these master clocksare identical and have the same contacts whlchare timed in the samemanner. In Fig. 4 the contacts and cams and wiring of the two masterclocks are generally shown at 21 and 210. Under normal conditions thesupervising master clock 21 controls the operation of the secondariesand only upon the failure of this supervising clock is the auxiliarymaster clock brought into the system to then control the secondaryclocks. The switch-over of the control of the secondary units of thesystem is effected by the operation of a multicontact relay. Thismulticontact relay is effected only upon the failure of themaster-clock, which causes contact 28 toclose thus energizing magnet 28which is the relay magnet of the multicontact relay. The contact 28which is normally open is also associated with another normally opencontact II and 9. normally closed contact ll. One of the blades 32extends outwardly beyond the other blade and coacts with an insulatedmember 83 fixed to an arm 34 pivoted at 35 to a fixed plate 36 on whichare also mounted the previously mentioned contacts. Substantially in thecenter of the arm ll is a cam follower 31 which wipes on a cam 3!. Whenthe clock system is in the correct operative condition the cam wiper llnormally rests in a notch 39 on said cam but with the stopping of eitherone of the clocks this cam is adapted to rotate in a clockwise orcounter-clockwise direction according to whether the auxiliary masterclock or the supervising master clock has stopped. The manner in whichthis cam is rotated will be explained later.

If the supervising master clock stops the cam will move one step in acounterclockwise direction as viewed in Fig. 3 causing contact ll toopen and contacts 30 and 28 to close and once this has taken place thecam ll will move no further. If the auxiliary master clock fails the cam38 will move one step in a clockwise direction causing contacts 3|! toclose and contact ll to open. It will be noted that contact 28 does notclose in' this event as the arm 34 is not actuated to the same extentwhen the cam moves clockwise as' it is when the cam movescounterclockwise. This is due to a cam plate II which is fixed to oneface of the cam 3} this plate having a camming surface adjacent to thecam wiper 31 and extending beyond the periphery of the cam ll so thatwhen the cam II moves counterclockwise the cam wiper'l'l cooperates withthe cam plate ll to move the arm 34 in a clockwise direction about itspivot point II a suflicient distance so that the insulated member 33cooperating with the blade 32 will lift that blade opening the contactII and closing contacts II and II. If, on the other hand, the cam 18moves in a clockwise direction, the cam follower moves out of its notchon to the periphery of the cam 3! which causes it to move the cam wiperless than half the distance as in the previous case thus causing onlycontact II to close and contact II to open but not moving the arm 34sumciently to close contact 2!.

The movement of the cam II is providedthrough the differential operationof in under the direct control of the two master clocks. These twomechanisms are generally shown in Fig. 2 and consist of two secondaryclock movements which may be mounted together by spacing studs IIextending between and rigi y 1 tened to front plates 5! and I20 whichconstitute the two front plates of the secondary movement. The secondarymovement may be of any suitable ratchet and pawl design of which thereare many to choose from.

In this application I have preferred the embodiment of the secondarymovement which is shown in my Patent No. 1,821,100, dated Septemher 1,1931, which describes in detail the operation of the secondary movementin which electrical impulses delivered each minute to masnets I3 .and53a operate a ratchet and pawl mechanism to rotate the ratchets H and"a. These ratchet wheels are fixed to shafts I! and "a and rotate theseshafts in opposite directions at relatively the same speed; that is,each magnet receives impulses at one minute intervals although theymight not necessarily coincide. Fixed to shaft 55 is a bevelled gear I!and mounted loosely on the shaft 55 at the extremity of said shaft wherethe diameter is reduced is a bevelled gear 51 having an axially extendedportion I which abutsthe shoulder formed by the larger diameter of theshaft 55 and which holds the bevelled gear in spaced relation to thebevelled gear I. At the extreme end of the shaft ll, said shaft isprovided with a still smaller and threaded diameter on which is screweda knurled nut 80 for bolding the gear 68 upon the shaft. Suchconstruction is that used generally for holding the minute hand on theminute arbor of a clock.

Fixed to the bevelled gear 51 is a bifurcated member 6| which engages anL-shaped arm l2, one end of which extends through the bifurcation ofsaid bifurcated member and the other end of which is fixed by meansof aknurled nut a to the shaft "a. Two planetary bevelled gears arerotatively mounted within a supporting member I (see P18. 3) to whichsupporting member is fixed the cam 38. The rotatively mounted bevelledgears 65 each mesh with both of the bevelled gears 56 and 51 thusproviding a differential gear mechanism capable of indicatingdifferences of relative motion of the two gears 56 and 58. Gear 6! isoperated in one direction by the secondary movement "a, whereas, gear 58is operated in the other direction by the secondary movement 50.

Thus if both of these movements operate the respective gears on theirarbors in opposite directions and at the same relative rate there willbe no change in the position of the cam ll due to the free rollingaction about the axis of the planetary gears 65, whereas, if one or theother of the secondary movements stop the cam II will rotate in eitherone direction or the other depending upon which one of the twomechanisms are caused to stop. As this differential action is old andfully understood by any one at all skilled in the art, it is believedthat no further or more detailed description need be given.

Turning now to Fig. 4, contact l'l closing every minute by virtue of theoperation of the cam associated therewith, all of which is described inthe patent to Bryce No. 1,687,491 previously referred to, operates relaymagnet ll once each minute thereby closing relay contacts H each minuteto transmit impulses from the positive supply line through line I2.contact II, to the secondary clock line A and then through one of thecontacts associated with the secondary clock when clwed, through themagnet which operates the secondaryclockandwhichare cally indicated atI! to the ground which is in turn connected to the negative part of theline. It is tobeunderstoodthatalternatingcurrentcanbe used in thisconnection as well as directcurrent but for the convenience of tracingcircuit. the terms positive and negative side will be used.

The operation of the relay coil II is eiiected through the followingcircuits. From the positive supply line through wire 14, switch", lowercontact blade It, back contact 'l'l, wire ll, multirelay contact 19,wire relay coil ll, contact II, wire Ii, multi-relay contact 82, relaycoil II and back to the negative side of the line.

It will be noticed that the minute impulses which operate master relaycoil II which in turn operates the secondary clock also operates there-. lav coil III which is in series with said master relay coil toclose contacts Ila once each minute. The closing of said contacts Ilaeach minute initiates minute impulses which are transmitted to thedifferential driving magnet 53 as follows: from the positive supply linethrough wire ill, contacts 80a. driving magnet 83, wire Iii, closedcontacts ll, wires 98 and 99 to the negative supply line.

The corrective or synchronizing feature of the secondary circuit istaken care of in the same manner as shown in the Bryce PatentNo.,l,68'l,49l previously referred to in which the 13 wire of thesecondary circuit is' periodically opened by the opening of relaycontacts 83 thus preventing the impulses initiated by closing of relaycontacts Ii being transmitted over the B wire.v This is accomplished byconnecting the relay magnet M in circuit with the contact ll as is shownin the Bryce patent thus establishing a circuit from the positive sourceof supply to wire ll, switch 16, line 85, contact ll, wire 88,multi-relay contact 31, wire 88, relay magnet 84 and back to thenegative side of the line. Thus the closure oi contact I at its properinterval will break the contact at 83 providing the bottom contacts ofthe multi-contact relay are closed. The rapid impulses for setting slowclocks ahead are initiated by the operation of the contact I! whichcloses every second or two seconds with the swing of the pendulum and isproduced by bringing this contact into circuit by the closure of contactIS in which a circuit will be established from the positive side of thesupply line, through wire ll, switch I5, contact i6, contacts l9,resistance RI wire ll, contact 82, master relay magnet 10 to thenegative side of the supply line.

The back contact I1 is provided in addition to the contacts shown in theBryce patent, in order to cut the relay magnet 80 and therefore thedifferential driving magnet 53 out of the circuit when rapid impulsesare sent through so that the rapid impulses will notail'ect the drivingmagnet and as the relay magnet 80 is normally in series with the relaymagnet III, a resistance BI is provided in the line to replace anequivalent resistance when the operations of the contacts I! and 11 cutin the resistance RI and cut out the relay magnet Oil.

The above explains the normal operation of the secondary clock systemfrom the master clock. During this normal operation the auxiliary clockalso operates but as its control contacts are connected to the uppercontacts of the multi-contact relay which are now open, it has noeilect' on the secondary clock system. There is one exception to theprevious statement regarding the multicontact relay, and that is, thatthe lower relay contact 80 is connected in circuit with the minuteimpulse contact "a oi the auxiliary master clock to operate the drivingmagnet a of the differential mechanism as follows: from the positiveside of the supply line, through wire 9|, wires 92 and 93, minuteimpulse contact Ila, wires 94 and l5, normally closed relay contacts I,wire 01'. multi-contact relay contacts iill, diflerential driving magnet58a, wires I I 0 and 98 back to the negative supply line. Both drives ofthe diilerential mechanism are thus simultaneously operated as long asthe master clock and the auxiliary master clock are running.

Relay magnet I" connected with the auxiliary master clock is in circuitwith the normally closed contact IM from the positive'side of the supplyline, through lower contact llll, through relay magnet I00 to thenegative side of the supply line thus keeping this magnet normallyenergized so that relay contacts 96 are normally closed.

The purpose of this is to prevent the rapid correcting impulses from theauxiliary master clock contact l8a from effecting the differential drivemagnet 53a during the period when contact lta closes to cut the rapidcorrecting impulses into circuit as when contact ita closes contact "IIwill open whereupon relay magnet lilll will become deenergized openingrelay contacts 98 and thus breaking the circuit to the differentialdriving magnet 53a. As contacts TI and "ll of the two master clocks openonly between minute impulsesof their respective master clocks the twodifferential driving magnets will not be cut oil from any oi! theregular minute impulses initiated by either of the master clocks.

In the operation of the differential mechanism, let it be assumed thatthe supervising master clock, the circuit of which is shown at the leftin Fig. 4 has stopped. In this case as contact ll nolonger functions thedifferential driving magnet 53 will no longer receive minute impulsesto' drive its respective side of the diilerentiai mechanism, whereas,the differential driving magnet 53a will continue to receive the minuteimpulses from the auxiliary master clock, the result being that upon thefirst or second impulse received by the driving magnet 53a after thediscontinuance of the operation of driving magnet 53, the cam 38 will bemoved in a counterclockwise direction and the cam wiper 31 will ride upon the cam plate I as previously described (see Figs. 3 and 4) openingcontact 3| and closing contacts 30 and 28. The opening of contact 3ibreaks the circuit through the differential drive magnet 53. The closingof contacts 28 and 30 cause the multicontact relay 29 to becomeenergized through the following circuit: From the positive supply line,through wire I02, multi-c'ontact relay magnet 29, wire I, contacts 28and 30, wires 98 and 99 to the negative supply line.

This circuit being established, the armature of the multi-contact relayis attracted to the magnet, thus opening the relay contacts 90, I9, 82,81 and II, which are the lower contacts and closing the upper contacts82a, 81a, and Mia. The opening 01' contact breaks the circuit to thedifferential driving magnet 53:: thus stopping the cam- 38 from furthermovement and leaving its associated contacts 28 and 30 in a closedposition and with contact 3| opened. The closure of contacts 82a and Ilaconnect the clock control relays l0 and 84 to the auxiliary masterclock. The minute impulse contact l'la operates the relay magnet 10through the following circuit: from the positive supply line throughwires 8| 92 and 83, contact "a, wire 94, contact 82a now closed, wire"l5, relay magnet 10, back to the negative side of the supply line.Contacts Ila control the relay magnet 80 through the following circuit.From the positive side of the supply line, through wires I and 92,contacts Ila, wire I06, contacts 01a (now closed). wire ll, relay magnetI4. and back to the negative side of the supply line. Thus the twosystem control relays are operated from identical correspondingly timedcontacts inthe auxiliary master clock as they were in the supervisingmaster clock. The closure of contact I040 causes a suitable signal to begiven to announce the failure of the master clock. This may be a soundsignal, such as a bell or a horn, or it may be a lightsignal. In thepreferred embodiment, a light signal is diagrammatically shown andiswperated from the following circuits: From the positive side of thesupply line. through wire Ill, electric light llll, wire its, uppercontact lMa (now closed), wires Ill and Q0, and back to the negativeside of the supply line.

As previously stated, when an attendant or service man has answered thetrouble warning of light Ill and hascorrected the condition and has setthe main operating master clock again: into operation, the cam 3! isreset which will open the contacts 28 and II thus deenergizingmulticontact relay magnet 28.

The deenergization of this relay causes the lower contact of this relayto again be closed whereby the driving magnet I3 and a, will resumeoperation under control of their respective master clocks and thesecondary clock system will resume operations under the control of thesupervising master clock.

In the event of failure of the auxiliary master clock the minuteimpulses initiated therefrom will cease thereby terminating theoperationof the driving magnet Ila, which will cause the cam II torotate in a clockwise direction upon the next succeeding impulses fromthe supervising master clock transmitted to the driving magnet II. Therotation of the cam II in a clockwise direction will cause the cam wiper31 to ride up on the periphery of the cam 38 causing contact 3| to openand contact 3| to close but as the rotation of the cam II in thisdirection does not -liftthecamwiperasfarasitdidintheprevious through thefollowing circuit: from the positive side of the supply line, throughwire llll, electric light il8,wire III, lower contact I III (nowclosed), wire Ill, contact III, wire II, and back to the negative sideof the supply line.

In this case also, after the attendant has taken heed of the warning andhas corrected the trouble in the auxiliary master clock the same is setto time and continues with its operation and the cam 38 is resetpreparatory to operating again to give warning upon the failure ofeither of the master clocks.

Only in the event of both master clocks stopping at the same time willthis throw-over device fail to operate but this constitutes such aremote coincidence that it is not necessary to con sider such apossibility in commercial application.

While the fundamental and novel features of the invention, as applied toa single modification is shown and described and pointed out, it

vwill be understood that various omissions and substitutes and changesin the form and details of the device illustrated and in its operationmay be made by those skilled in the art without departingfrom the spiritof the invention. I intend to be limited therefore only as indicated bythe scope of the following claims.

Whatis claimed is as follows:

1. An electric clock system including two master clocks and a pluralityof secondary clocks controlled thereby, a differential mechanismoperable by both master clocks conjointly, contacts operable by saiddifferential mechanism for transferring the control of said secondaryclocks from one master clock to the other.

2. An electric clock system including two master clocks and a pluralityof secondary clocks controlled thereby, means for transferring thecontrol of said secondary clocks from one master clock to the other,said means comprising a member operable from each of the said masterclocks, a cam operable by the relative movement ofsaid members, contactmechanism operable in accordance with the movement of said cam, and arelay operable by said contacts for effecting the transfer of thecontrol of said secondary clocks from one master clock to the other.

3. An electric clock system comprising two master clocks, a plurality ofsecondary clocks adapted to be operated by one or the other of saidmaster clocks, means operated conlointly by both ondary clocks.

CLINTON E. LARRABEE.

